This invention relates to self-closing caps for squeeze-type containers from which the contents is extruded by the application of pressure on the body of the container and in which the lips of the cap close when squeeze pressure is removed from the container.
Heretofore, a number of self-closing caps have been proposed which allow for the extrusion of the content of a deformable container, also referred to as squeeze container, which contains substances such as tooth paste, shaving crean, paints, glue, sauces, food pastes and practically any substance which has a relatively smooth consistency and a viscosity allowing it to be extruded. The term squeeze-type or deformable container includes resilient containers which after being squeezed return to their original shape and deformable containers such as toothpaste tubes which retain their deformed shape.
Generally speaking, deformable containers are used where the substance in the container is to be protected from the exposure to air such as paints, wines etc, or water in case of underwater applications, and resilient containers are used where exposure to air would not be harmful and the substance is to be kept clean and sanitary.
Self-sealing caps for such containers have many advantages in that they require only one hand for dispensing the substance without the necessity of sealing after such dispensing. Such caps also result in a substantial savings in the manufacture of containers and convenience because the normal closure member, such as the threaded cap or stopper and the like, is expensive to manufacture and is easily lost resulting usually in damage to the contents. One particular cogent example is toothpaste or paint which, if left open, will harden because of its exposure to air and therefore become unusable. As far as foods are concerned, contact with air often causes contamination of the food requiring it to be discarded which is most wasteful. In some other instances, lack of closure results in dehydration and the subsequent spoiling of the contents.
There have been many self-closing caps proposed by the prior art but none have shown much commercial success. One major reason for such lack of commercial success may be due to the fact that the prior art self-closing caps did not provide a sufficiently tight seal to prevent air and foreign matter from reaching the substance to be contained. Another major reason for lack of commercial success may be due to the fact that most substances that can be placed into a squeeze-type container are thicker than water and the lips of the prior art self-sealing containers are unable to sever the contents to properly close. Another major reason for the lack of commercial success for the prior art self-closing caps may have been a lack of cleanliness in that much of the substance collected on the outer faces of the lips forming the slit-like opening and became hard and crusty and therefore unsanitary and also interfered with the subsequent extrusion or the proper sealing of the slit-like opening.